Many studies have been made on regenerative medicine which regenerates cells, tissues, and organs lost due to diseases or accidents by artificial materials or cells.
Normally, a body has a self-protection function, and when a foreign substance such as a prickle intrudes into a shallow position in the body, this substance is to be pushed out of the body. It is also known that, when a foreign substance intrudes into a deep position in the body, fibroblasts gradually gather around it and form a capsule of connective tissue mainly made of the fibroblasts and collagen so as to cover the foreign substance and to isolate the foreign substance in the body. As technologies for forming a biological origin tissue from living cells by using a self-protection reaction of the latter, several technologies for forming a connective tissue body by implanting a substrate as a foreign substance in a living body have been reported (see Patent Literatures 1 to 3).
Moreover, Patent Literature 4 discloses a substrate which forms a film connective tissue body having a desired thickness and both surfaces in a desired surface condition by forming a connective tissue between two connective tissue formation surfaces facing each other by arranging a substrate in a living body or the like.